The present invention relates to a new and improved construction of a shutoff element for gaseous media containing a device or means for damping self-excited acoustical vibrations or oscillations in cavities of the like. These acoustical vibrations arise because the flow channel for the medium has a cavity in which there are located an impact zone and a dam-up point for part of the throughflowing gaseous medium.
At high flow velocities at the region of cavities, where the flow jet of the operating or working medium bears at one side against a wall and which jet of working or operating fluid medium effluxes out of a nozzle-like constriction or throat following the seat cross-section of shutoff elements, acoustical vibrations or oscillations occur at such shutoff elements. The amplitude of these acoustical vibrations reacts with great sensitivity upon the intensity of the mass flow vibrations or oscillations and the dam-up point vibrations at the impact zone of the flow at the outlet of the cavity. The more intense the dam-up point oscillations react upon the pressure oscillations in the impact zone that much more intense will there be dampened the vibrations or oscillations in the cavity.